Various related techniques for reducing the number of operating servers and power consumption are known.
For example, there is a technique for reducing the number of operating servers and power consumption by devising the disposition of virtual machines. This technique includes a static disposition processing technique and a dynamic disposition processing technique. The static disposition processing technique is a technique in which demanded performance for a server is predicted from a past log or the like and a plan for controlling the number of operating servers is previously created. On the other hand, the dynamic disposition processing technique is a technique in which according to a load situation of a server or a system including the server at different times, the number of operating servers is controlled.
PTL 1 discloses a machine operation plan creation device. The machine referred to here is a physical computer or a virtual machine. This virtual machine is a virtual computer obtained by dividing computer resources of one physical computer into a plurality of virtual computers. Further, a physical computer virtual machine assumed to provide some sort of service is also referred to as a physical server. Similarly, a virtual machine assumed to provide some sort of service is also referred to as a virtual server.
The effect of the machine operation plan creation device described in PTL 1 is to create an operation plan so as to reduce the number of operating machines providing a web service in each time slot and also to minimize the operation number of starts and stops of the machines. The web service is a service in which a server returns a certain calculation result to a request from a client in a relatively short time (at least several seconds). The performance of the web service is represented by tps (Transaction Per Second) or the like that is the number of requests (transactions) processable per second.
In general, the performance needed for a certain web service changes with a time slot and has periodicity. Further, the number of requests processable by a certain machine is constant. Therefore, to process a large number of requests, there is used a method for enhancing processing performance by clustering a plurality of machines and distributing (load-dispersing) the requests among these machines. In such a configuration large in size, the number of machines necessary for each time slot varies.
The machine operation plan creation device described in PTL 1 receives a list of the number of machines needed in each time slot and creates an operation plan so as to minimize the number of starts and stops of each machine based on the list. Thereby, the machine operation plan creation device reduces the number of operating machines and power consumption thereof and also reduces trouble of setting changes, a risk of missetting, and the like associated with machine addition (start) and reduction (stop).
PTL 2 discloses a server management device. The server management device described in PTL 2 is a device that manages a plurality of cluster systems for providing a plurality of services.
The server management device described in PTL 2 includes a load information collection unit, a configuration information collection unit, a configuration change determination unit, a configuration change target selection unit, and a configuration change execution unit. The load information collection unit collects load information of a virtual server group configuring the cluster systems. The configuration information collection unit collects information as to which physical servers the virtual servers are allocated, as configuration information. The configuration change determination unit determines whether the number of virtual servers can be reduced from the load information. The configuration change target selection unit selects a physical server allocated with the fewest number of operating virtual servers by referring to the configuration information. The configuration change execution unit stops the virtual servers on the selected physical server. Further, the configuration change target selection unit selects a physical server allocated with the most number of operating virtual servers. Further, the configuration change execution unit starts the virtual servers on the selected physical server.
The server management device having such a configuration produces an effect in which the virtual servers on the physical server allocated with a small number of operating virtual servers are moved (biased) onto another physical server and the physical server allocated with no operating virtual machine is stopped to easily reduce power consumption. This effect is more markedly obtainable by intentionally creating a physical server allocated with a small number of operating virtual servers.
PTL 3 discloses a server migration plan creation system. On the basis of the respective amounts of resource use of source servers and the respective resource capacities of destination servers, the server migration plan creation system described in PTL 3 creates a server migration plan for allocating the destination of the source server to any one of the destination servers. The server migration plan creation system selects the source servers one by one in descending order of the amounts of resource use. Then, the server migration plan creation system selects any one of the destination servers and compares a target use amount that is the amount of resource use of the previously selected source server and a remaining amount of the resource capacity of the selected destination server. Then, when the target use amount is larger than the remaining amount of the resource capacity, the server migration plan creation system selects a destination server other than the already selected destination server and performs the comparison again. Further, when the target use amount is at most the remaining amount of the resource capacity, the server migration plan creation system allocates the selected destination server as the destination of the selected source server.